Device for remote surveillance of the current supply to an electrical apparatus

Abstract

The present invention is concerned with a device for observing from a distance the change of mode in feed current by city current of an electrical appliance by means of a telephone line characterized in that it comprises: means for detecting the presence or the absence of city current to the feed terminals of the electrical appliance, control means, triggered by the detecting means when there occurs a change of mode in the feed of said electrical appliance, switch means, capable of placing the telephone line either in a first free position or in a second engaged position, the control means acting upon the switch means to reverse the position of the telephone line when the detecting means detect a change of mode in the feed of said electrical appliance by city current. (FIG. 1).

I claim: 
     
       1. A device for observing from a distance the change of mode of current feed by city current to an electric appliance by means of a telephone line (8,10) in which the telephone line can be checked from a distance away from the electric appliance by calling the telephone line for checking the status of the telephone line and determining whether the telephone line is busy or not, thereby determining the current feed, comprising: detection means (2,31,62) for detecting the presence or the absence of city current to the feed terminals (12,14) of the electric appliance (13),   control means (2,31,65) triggered by the detecting means (2,31,62) when there occurs a change of mode in the feed of said electric appliance (14),   switch means, (4,35,66) capable of placing the telephone line (8,10) either in a first free or non-busy state or in a second engaged or busy state, and   the control means (2,31,65) acting on the switch means (4,35,66) to reverse the state of the telephone line when the detecting means detect a change of mode in the feed of said electrical appliance (14) by household current.   
     
     
       2. The device according to claim 1 wherein the detection means (2,31,62) are electrically isolated from said switch means (4,35,66). 
     
     
       3. The device according to claim 1, wherein the switch means (4,35,66) connect an electrical resistance (15,123) to terminals (8,10) of the telephone line giving a "busy" mode, said electrical resistance having a rating between 500 and 1200 ohms. 
     
     
       4. The device according to claim 3 wherein the electrical resistance (15,123) is connected when the city current is cut off. 
     
     
       5. The device according to claim 1 wherein the detection means for detecting the presence or the absence of current at the terminals of the electrical appliance (14) are constituted by means for emitting beams of light (31). 
     
     
       6. The device according to claim 5 wherein said beam emitting means is a photoemitting diode (31). 
     
     
       7. The device according to claim 1 wherein the control means comprise a phototransistor (36). 
     
     
       8. The device according to claim 1 wherein the detection means (31) and control means (35) are constituted by an optical coupler. 
     
     
       9. The device according to claim 1 including an electric supply for the control means (2,31,65) and/or switch means (4,35,66), said electrical supply means being affected by telephone line (8,10) voltage. 
     
     
       10. The device according to claim 9 include rectifying means (70), filtering means (72,73) and stabilizing means (71) for the voltage supplied by the telephone line. 
     
     
       11. The device according to claim 1 wherein the detection means (62) and the control means (65) are connected with timing means (63,64). 
     
     
       12. The device according to claim 11 wherein the timing means (63,64) are constituted by a frequency adjustable oscillator, feeding counting means (97,99). 
     
     
       13. The device according to claim 11 wherein the control means includes electronic logic means (65) and timing means (67, 97, 99) maintaining connection of a charge resistance (123), after the lapse of a given time from a first interruption of current as a result of a first disappearance of city current. 
     
     
       14. The device according to claim 11 wherein the control means includes electronic logic means (65) maintaining connection of the switch means, after the lapse of a given time from a first interruption, this time beginning at the instant of the first cut in city current occurring after connection of the device with the telephone line. 
     
     
       15. The device according to claim 2, wherein the switch means (4,35,66) connect an electrical resistance (15,123) having a rating between 500 and 1200 ohms to terminals (8,10) of the telephone line to provide a "busy" mode when current passes through said electrical resistance. 
     
     
       16. The device according to claim 5, including an electrical resistance (15,123) which is connected when the city current is cut off. 
     
     
       17. The device according to claim 1, wherein the control means includes a logic control unit for maintaining connection of a charge resistance (123), after the elapse of a given time, from a first interruption causing disappearance of city current. 
     
     
       18. The device according to claim 1, including a logic control unit forming part of said control means to maintain connection of the switch means, after a lapse of a given interruption time from a first interruption, this given interruption time beginning at the instant of a first cut in city current occurring after connection of the device with the telephone line, and comprising durations related to the duration of future interruptions in current.